A dozen years after the event, the attacks on American soil are still in our memories, haunting reminders that even the most powerful nation on the planet has vulnerability.

Today, many Americans will take a moment to remember those who lost their lives to senseless violence precipitated by enemies who hate the freedoms that our people enjoy. In addition to those who lost their lives in the hijacked jetliners and their targets — the Twin Towers in New York and the Pentagon — others perished in heroic attempts to help the victims.

At 8:46 a.m., the time when the first jetliner slammed into the WTC, a number of Americans will pause today for a prayer or just a moment of silence. In that instant in 2001, our perspective of the world changed. The thought that the vast oceans and our military might could keep at bay this sort of brutal, mindless killing was shattered as smoke billowed from the towers and they fell to the ground.

A great deal has transpired since that day, including two wars from which we’re only now extricating ourselves.

We learned that the current generation, untested before 9/11, was capable of rising to the occasion. We learned that Americans can look past the superficial and band together, holding each other up in times of crisis. We were reminded of the great level of sacrifice that those in our public safety agencies — law enforcement, firefighting, emergency medical personnel — and military make every day, the image magnified under the extraordinary circumstances we faced. Many of us found a renewed sense of family and community.

On the other hand, we’ve also been too willing to give up freedom and privacy to government scrutiny. Our political system has become increasingly dysfunctional and polarized. The solidarity that Americans felt in the wake of 9/11 has waned, and the things we once found insignificant in the face of a crisis have again claimed much of our focus. Too often civility is shunned and abrasiveness celebrated. We seem to look for things to separate us, not bring us together.

And that is something we need — a sense of togetherness, a real concern for our fellow citizens.

The fact is, the danger may have been muted over the years, but it is not gone. Like a snake hiding in a wood pile, those who want to bring America to its knees are plotting and patiently waiting for an opportunity to strike. They struck in Benghazi. They struck at the Boston Marathon. Despite any number of other failed attempts, they wait.

And that is something that should be remembered today. A life lived in constant fear is no life, but failure to be watchful will cut life short.

We should never forget and we should never forget to appreciate those who place themselves in danger on a daily basis on our behalf. In Albany, those people will be front and center. The Marine Corps Logistics Base will have an observance this morning. This evening, Covenant Presbyterian Church has taken on the task of serving free meals to law enforcement officers, firefighters and emergency medical technicians.

When you see these people — our military and public safety personnel — you’re looking at America’s first lines of defense. You’re looking at the people who will place their lives on the line for yours, whether in response to an attack by terrorists or any other number of dangers, from criminals on the streets to fires to natural disasters.

Today is an excellent time to say two simple words to these brave men and women: Thank you.